Often they do go back and forth the whole way, and I don't know until the very end what the last line of the book is going to be. That was true here - the very last line of the book was the last thing that happened.

There will be scenes in a movie where people are walking through the park, or through a forest, and you're seeing the flickering leaves around them, and they're walking, but you're also hearing their words. It's an interaction between where they are and what they're saying that's both visual and verbal.

Ideas mostly come from the work itself. Often when I'm drawing, the words will be bouncing around in my head, and when I'm writing, ideas about the drawing happen.

Some of it just involved thinking about, for example, the different kinds of science, what chemistry is.

It's really daunting when you have just spent a lot of time on something to think about tossing it out. But once you've started something better that's working right, then it's pretty easy to let the first one go.

I remember when I was working on All Alone in the Universe, and Robin Roy was my editor. When I first sent it to her, she said kids this age don't want pictures in their books.

I generally have an idea where I want to go, but I don't know how I'm going to get there.